I just finished packaging Docker 18.09.0 (release on 2018-11-08, see
aports). To do this I had to split out containerd and runc into own
packages - as they should no longer be directly packaged into the docker
main package (according to the release notes of docker).

One advantage of this new packaging will be that one is able to run
containerd and / or runc without using docker. I think I already read some
comments / wishes about this on IRC.

One could also use another container runtime instead of runc in the future
- together with docker or without docker. So maybe we will see some more

I would like to maintain these packages in the future. If noone is against
it (_at_ncopa ?). The next regular release of docker will be 19.03 somewhere
in march / april 2019 BTW.